package com.kuang.servlet;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URLEncoder;

public class FileServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        1、要获取下载文件的路径
//        String realPath = "E:\\代码\\javaweb\\javaweb-02-servlet\\java-web_study\\response\\src\\main\\resources\\cat.jpg";
        String realPath = "F:\\FileCode\\JavaWeb\\javaweb-02-servlet\\response\\target\\classes\\cat.jpg";
        System.out.println("下载文件的路径："+realPath);
//        2、下载的文件名是啥？
        String fileName = realPath.substring(realPath.lastIndexOf("\\")+1);
//        3、设置想办法让浏览器能够支持(Content-Disposition)下载我们需要的东西
        resp.setHeader("Content-Disposition","attachment;filename="+ URLEncoder.encode(fileName,"UTF-8"));
//        4、获取下载文件的输入流
        FileInputStream in = new FileInputStream(realPath);
//        5、创建缓冲区
        int len = 0;
        byte[] buffer = new byte[1024];
//        6、获取OutputStream对象
        ServletOutputStream out = resp.getOutputStream();
//        7、将FileOutputStream流写入到buffer缓冲区,使用OutputStream将缓冲区中的数据输出到客户端
        while ((in.read(buffer)) > 0){
            out.write(buffer,0,len);
        }
//        8、关闭流
        in.close();
        out.close();
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}
